View Single Post
Old 06-16-2010, 11:59 AM   #88 (permalink)
usergone
I have to start over?
 
Join Date: May 2010
Posts: 214

Big inefficient truck - '94 Dodge Ram 2500
90 day: 12.1 mpg (US)

Honda Civic - '84 Honda Civic DX Hatchback
Thanks: 2
Thanked 8 Times in 7 Posts
Well... Looks like I get to jump on the peak and hold bandwagon as well. I have had the guino hooked up to my car, even without the vss, and noticed that the GPH only changes with RPM. I thought that was odd, because even if I floored it, the GPH would not change (until the RPMs went up)

So I measured the TBI injector... Yeah... 2 ohms...

Quote:
Originally Posted by dcb View Post
it looks like they use a shunt resistor and an op-amp. Not sure how it gets dialed in. The opto works by the voltage drop across the inector (for negative switched systems).
I was just thinking that I could use a shunt (if we're trying to measure current). I have no problem cutting my injector lead, or both leads for that matter. I already have one cut and spliced to my kill switch.

For clarification, all of these schemetics are going on the assumption that I am looking at a waveform like this:

...and want to pay attention to the "C" section.

Maybe like this?


The "A" lead would (I think) give a voltage signal that is proportional to the current. I have a LM358N opamp on hand, but can't say I know just how to hook it up! (the technical stuff, I think I have the basic logic idea)

Then maybe use this circuit?


Or, if you want a top trim (cut it off above X voltage)... (BTW, I am pretty sure I have the transistor in there wrong. I want it to be when the A input is higher that X voltage (controlled by the pot on the right) the output goes low, and makes the transistor cut off the current from the left side)


Wow, long post
  Reply With Quote